wut? please explain further, from what i got out of that your led is not strong enough. but please explain a bit more on your setup and what is going wrong with it so i can help you more.

FOR BLACK LINE FOLLOWER

Actually that circuit i got from pratheek in society of robot website (line follower without microcontroller). Actual is LDR with LED. From there, i got think of trying to use photodiode to see what will happen further. From the basic learning that i know photodiode must receive reflection from the infrared light then only will give respond to it.

After i built up everything completely, I found out that LDR can use in any surface but must have light and dark surface because light surface is for LED to transmit the light so the light will reflect back to the LDR while dark surface will absorb maximum light. While i try to test photodiode on the light and dark surface same as i try on LDR, it does not give any respond to it. This make me crazy , then i try to get the mirror (women love to use mirror when doing make up) and try on it. Finally, it give respond to the photodiode.

In conclusion, i think infrared LED need the surface such like mirror to reflect the infrared light to the photodiode while LED (normal LED) need the light surface (like white paper) to reflect the LED light to the LDR. LED oso able to use on the mirror because mirror also is light surface but infrared LED cant use on white paper because of the surface.

In conclusion, i think infrared LED need the surface such like mirror to reflect the infrared light to the photodiode while LED (normal LED) need the light surface (like white paper) to reflect the LED light to the LDR.

Nah, you just need to get your circuitry and its sensitivity right for the given purpose.

Please post the schematic of the exact circuit you build and we can advice the changes necessary.

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Regards,Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?Please remember...Engineering is based on numbers - not adjectives

In conclusion, i think infrared LED need the surface such like mirror to reflect the infrared light to the photodiode while LED (normal LED) need the light surface (like white paper) to reflect the LED light to the LDR.

Nah, you just need to get your circuitry and its sensitivity right for the given purpose.

Please post the schematic of the exact circuit you build and we can advice the changes necessary.